Portable Glulam Timber Bridge Design for Low-Volume Forest Roads

Improved stream crossings are needed to reduce construction and maintenance costs and reduce the environmental impacts from low-volume forest roads and skid trails. New designs of timber bridges are cost-effective alternatives for portable stream crossing structures. This paper discusses design criteria for portable timber bridges and presents one design for a portable, longitudinal glued-laminated (glulam) deck timber bridge. Design criteria for portable bridges generally should not be as conservative as those used in the design of permanent highway bridges. The longitudinal glulam deck bridge has performed well in service, and load test results demonstrate that highway bridge design procedures are conservative for portable bridge systems.